VM terminates when evaluating any expression for class that extends using itself as a type arg

[DanTup]

This issue was reported to me on Dart-Code's discord. I was able to reduce it to the following:

import 'dart:developer';

void main(List<String> args) {
  final a = A<C>();
  debugger();
}

class A<T> {
  A();
}

class B<T> {
  final T data;
  B(this.data);
}

class C extends B<C> {
  C(C data) : super(data);
}

Running this code under the debugger will pause on the debugger() line. Trying to evaluate any expression at all (even 1) will terminate the VM and the response looks like this:

{
	"jsonrpc": "2.0",
	"error": {
		"code": -32000,
		"message": "Bad state: The client closed with pending request \"evaluateInFrame\".",
		"data": {
			"full": "Bad state: The client closed with pending request \"evaluateInFrame\".",
			"stack": "",
			"request": {
				"id": "35",
				"jsonrpc": "2.0",
				"method": "evaluateInFrame",
				"params": {
					"disableBreakpoints": true,
					"expression": "1",
					"frameIndex": 0,
					"isolateId": "isolates/2111979752828675"
				}
			}
		}
	},
	"id": "35"
}

There is no other error message information (via the VM Service or stderr/stdout) that I can get.

I'm not sure whether class C extends B<C> { makes a lot of sense (it seems like it's impossible to call C's constructor here, since you need to pass a C to it) but I wouldn't expect a crash.

@bkonyi

[a-siva]

https://dart-review.googlesource.com/c/sdk/+/247901

[DanTup]

@a-siva should this be closed (https://dart-review.googlesource.com/c/sdk/+/247901 shows as merged), or is there anything left to do?

Thanks!

[bkonyi]

Yup, this should be closed (@a-siva is out this week).